I have been having the same Problem, it's so random I cannot isolate the cause, I read somewhere to make sure your usb ports are not set up to go to save power mode, I have done that but then again I have had it happen coming out of a dmd game, I think my problems started after I had set up FX2 and dmdext a while back, I took FX2 off and I am just running Visual Pinball now so I am assuming something is lingering on the system still. I have been considering just doing a clean install. I didn't have the problem when I originally got the cabinet going. I was hoping someone had seen this also and had an easy fix